DNA, RNA

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DNA, RNA Protein Synthesis
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I. What are Proteins?

• Proteins are organic molecules made of various
  arrangements of 20 amino acids
• Examples-
• 1. Enzymes.
• 2. Transport proteins and receptor molecules
  in cell membranes
• -ex. hemoglobin

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I. What are Proteins? (cont)

1. Hormones- ex. Insulin, adrenaline, testosterone
2. Structural proteins- ex. Keratin and collagen in
   skin, actin and myosin of muscle.

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I. What are Proteins? (cont)

1. Antibodies
2. Storage molecules- ex. Albumin in egg white,
   casein in milk, and plant proteins in seeds.

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II. How are proteins made?

• Amino Acids are put together at the ribosome to
  form proteins
• The order in which the amino acids are to be
  arranged depends on the instructions from your
  genes
• which can be found in the control center
• the nucleus
• which contains DNA
• where your genes are found

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III. What is a Gene?

• A gene is a length of DNA that codes for a
  protein (or one subunit in a protein.)

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IV. What is DNA?

• Deoxyribonucleic Acid

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A. DNA Structure

• The structure of DNA was first described by
  Watson Crick in 1953.
• Double helix- twisted ladder

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A. DNA Structure

• 2. The DNA molecule is made up of Nucleotides.

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B. A Nucleotide the building blocks of DNA

• 1. Sugar
• 2. Phosphate group (phosphoric acid)
• 3. A Nitrogen base
• So for DNA
• the sugar deoxyribose
• phosphate group
• nitrogen base (4 different kinds)
• Adenine
• Thymine
• Cytosine
• Guanine

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C. Shape of DNA-twisted ladder
S

1. Sides of the ladder sugar phosphate
2. Rungs (steps) nitrogen bases

S
NB
P
P
S
S
NB
P
P
NB
S
S
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Shape of DNA-twisted ladder(cont)
S

• 3. sugar phosphate are held together by strong
  covalent bonds
• 4. nitrogen bases are held together by weak
  hydrogen bonds

S
NB
P
P
S
S
NB
P
P
NB
S
S
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D. The Nitrogenous Bases

• 4 nitrogenous bases of DNA
• a. Adenine
• b. Thymine
• c. Cytosine
• d. Guanine
• Base-Pairing Rule
• Adenine pairs with Thymine (A-T, T-A)
• Guanine pairs with Cytosine (C-G, G-C)

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E. DNAs Problem

• DNA cannot leave the nucleus.
• So, How does it get the instructions to the
  ribosome?....
• RNA

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V. What is RNA?

• Ribonucleic Acid

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A. RNA Structure

• RNA is made up of nucleotides.
• Sugar Ribose
• Phosphate Group
• 4 Different Nitrogen Bases
• Adenine
• Uracil
• Cytosine
• Guanine

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A. RNA Structure

• Base-Pairing Rule-
• Adenine pairs with Uracil
• Cytosine pairs with Guanine
• 3. RNA is single-stranded.
• 4. RNA can leave the nucleus.

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B. Types of RNA

1. mRNA- messenger RNA takes DNAs instruction from
   the nucleus to the ribosome.
2. tRNA- transfer RNA brings an amino acid from the
   cytoplasm to the ribosome.
3. rRNA- ribosomal RNA

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C. Going from DNA to mRNA to tRNA
(one side)DNA strand pairs with mRNA strand pairs with tRNA strand
A U A
T A U
C G C
G C G
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VI. How does DNA give the message to RNA?
Transcription

• Transcription is the process of DNA making RNA.

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B. Steps of Transcription
deoxyribose
ribose
phosphate
uracil
adenine
thymine
cytosine
guanine
DNA strand

• 1. The DNA strands separate at the H-bonds
  holding the nitrogen bases together. An enzyme
  causes the unwinding.

The Nucleus
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B. Steps of Transcription
deoxyribose
ribose
phosphate
uracil
adenine
thymine
cytosine
guanine
DNA strand

• 2. mRNA (messenger RNA) pairs up with DNA

The Nucleus
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B. Steps of Transcription
deoxyribose
ribose
phosphate
uracil
adenine
thymine
cytosine
guanine
DNA strand

• 3. The mRNA nucleotides covalently bond.

The Nucleus
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B. Steps of Transcription
deoxyribose
ribose
phosphate
uracil
adenine
thymine
cytosine
guanine
DNA strand

• 4. The DNA strands will bond back together.
• 5. The mRNA chain can now leave the nucleus
  goes to Ribosome.

The Nucleus
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B. Steps of Transcription
deoxyribose
ribose
phosphate
uracil
adenine
thymine
cytosine
guanine
DNA strand

• 6. Where is mRNA going? to a
  ribosome

The Nucleus
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VII. What Happens at the Ribosome? Translation

• Translation is protein synthesis and occurs on a
  ribosome.
• The ribosome is a protein-RNA structure with two
  binding sites for a mRNA molecule. It will read
  2 codons at a time.
• A codon is 3 nucleotides of mRNA.

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nucleus
U
mRNA
C
C
C
A
A
U
U
U
A
U
G
G
mRNA
codon
codon
codon
codon
cytoplasm
ribosome
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C. Steps of Translation

• First mRNA binds to the ribosome at the START
  codon (AUG) of mRNA.
• A tRNA (transfer RNA) molecule with an anticodon
  at one end and an amino acid at the other binds
  to the first codon of mRNA.
• an anticodon is 3 nucleotides of tRNA

Thank you to Lew-Ports Biology Place !
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nucleus
tRNA
anticodon
A
G
A
U
C
mRNA
C
C
C
A
A
U
U
U
A
U
G
G
mRNA
codon
codon
codon
codon
START
cytoplasm
ribosome
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C. Steps of Translation

• The second tRNA binds to the second codon of
  mRNA.
• 4. The first two amino acids bond.

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proline
START
nucleus
tRNA
tRNA
anticodon
A
G
G
mRNA
C
C
C
A
A
U
U
U
A
U
G
G
mRNA
codon
codon
codon
codon
cytoplasm
ribosome
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proline
valine
START
nucleus
tRNA
anticodon
A
U
C
mRNA
C
C
C
A
A
U
U
U
A
U
G
G
mRNA
codon
codon
codon
codon
cytoplasm
ribosome
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C. Steps of Translation

• 5. This process continues until a STOP codon
  is read by the ribosome
• 6. An amino acid chain is the result

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proline
valine
leucine
START
nucleus
tRNA
anticodon
anticodon
A
A
G
U
mRNA
C
C
C
A
A
U
U
U
A
U
G
G
mRNA
codon
codon
codon
codon
cytoplasm
ribosome
cytoplasm
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D. Result of Translation

1. Proteins are the result of translation
2. 3D shape from ER.
3. It can then be used in the cell or released from
   the cell into the organism.

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• DNA Workshop Activity